Characteristics of the stomal apparatus of rare species of the genus Citrus in the conditions of wet subtropics of Russia

The article presents the characteristics of the stomatal apparatus in the leaves of 13 forms of 10 species of the genus Citrus: C. aurantifolia ('Tahiti', 'Foro'), C. limon 'Del brasil', C. ? meyeri, C. ? limonelloides, C. ? bergamia, C. ? limetta 'Chontipico', C. ? aurantiummyrtifolia 'Cinotto', C. ? ichangensis, C. maxima 'Sambokan', C. medica (var.sarcodactylis, citrate). As a result of the analysis of the stomatal apparatus, differences in the size of the stomata and their density per 1 mm2 were revealed. The greatest number of stomata per 1 mm2 was observed in C. medica, C. medica var. sarcodactylis, C. ? meyeri, C. aurantifoliavaried within 710,0–882,5 pcs/mm2, the smallest amount was in C. ? aurantiummyrtifolia 'Cinotto', C. aurantifolia 'Tahiti', C. limon 'Del Brasil', C. ? bergamia within the range of 277,5–490,0 pcs/mm2.The studied forms were divided into two groups: forms with a small number of stomata, with a relatively large leaf area – C. limon 'Del Brasil', C. ? bergamia, C. ? ichangensis, C. maxima ’Sambokan'; forms with a high number of stomata with a relatively small leaf area – C. aurantifolia (sour, 'Tahiti', 'Foro'), C. ? meyeri, C. ? limonelloides, C. ? limetta 'Chontipico', C. ? aurantiummyrtifolia 'Cinotto', C. medica. The largest stomata sizes were observed for C. aurantifolia 'Tahiti', C. limon 'Del Brasi', C. x aurantiummyrtifolia 'Cinotto'; length varied 24.8–27.9 ?m, width – 21,3–23,3 ?m, the smallest stomata sizes in C. aurantifolia, C. ? bergamia and C. medica are 21.4–23.4 µm in length and18,2–19,3 µm in width. C. aurantifolia C. ? `meyeri` and C. medica var. sarcodactylis which have a high density and small stomata.